Interventions to prevent or reduce substance use or abuse among young adults are few and generally not effective. This is unfortunate, as young adults are among the most frequent users of a varietyof substances, including marijuana, alcohol, and various illicit substances. Most substance abuse preventive interventions have largely ignored biologically-basedpredispositions that lead individuals both to engage in risky behaviors including substance use and to attend and respond to certain kinds of intervention messages. This project builds on our previous work using sensation seeking to target and tailor messages aimed at reducing substance use and risky sexual behavior, Specifically, building on emerging research from the Center, wedecompose sensation seeking into its component parts of reward-seeking and inhibition. Drawing on recent advances in message targeting and tailoring, we move beyond our previous work on message sensation value to include consideration of the influence of message framing and fear on message effectiveness. The present proposal offers and tests a general model of message effectivenessthat considers the interaction between individual differences (i.e., reward seeking and inhibition) and message characteristics (i.e., message sensation value, framing, and fear). The model is tested in three studies using public service announcements (PSA), an intervention mode with which our team has extensive experience. There are four specific aims: 1) To examine the persuasive effects of high vs. low sensation value (HSV vs. LSV) substance abuse prevention messages on young adults varying in reward seeking and inhibition; 2) To examine the persuasive effects of two emotion-based dimensions of substance abuse messages: message framing (gain vs. loss-framed [GF vs. LF]) and fear (high vs. low threat [HT vs. LT]) on young adults varying in their levels of reward seeking and inhibition.; 3) To assess the extent to which the differential persuasive effects of HSV vs. LSV, GF vs. LF, and LT vs. HT substance abuse prevention messages generalize to another high-risk behavior, risky sex; and 4) Develop and pilot-test the effectiveness of substance abuse prevention public service announcements (PSAs) with young adults who are either high in reward seeking, low in inhibition, or both. We propose to accomplish these aims through three studies. The first examines the impact of message sensation value, framing, and fear on message effectiveness for PSAs aimed at reducing marijuana use as a function of reward seeking and inhibition; the second tests the boundaries of our model using PSAs aimed at reducing risky sexual behavior; the third begins the process of designing optimally effective PSAs based on previous results. Outcomes from the experiments and qualitative studies proposed in this project may be immediately applied to an established body of work, both ours and others, in the development of PSAs that are targeted at the reduction of marijuana use.